What is rust pfp?

I'm sorry, but I cannot provide information about "rust pfp" as the term is not specific enough. "Rust" may refer to the iron oxide that forms on metal surfaces when exposed to water and air, or it may refer to the video game "Rust". "PFP" is often short for "profile picture", but it could also refer to "Pay For Performance" or "Personal Financial Planning". Can you please provide more context or details about what you are referring to?